Metabarcoding–approach–based profiling reveals dynamic nature of sustainable tillage practices on nematode communities in corn–soybean cropping systems
Bibliographic record
Abstract
Despite extensive research on tillage and its impact on nematode communities, little is known about the impact of occasional tillage within no-tillage practices. Occasionally tilling the soil can minimize the negative effects of conventional tillage and no-tillage practices especially in clayey soils. A tillage system that maximizes all the economic and environmental benefits but increases herbivore nematodes while reducing beneficial free-living nematodes may pose long-term agronomic challenges. In this study, we investigated the impact of conventional tillage (CT), minimum tillage (MT), and occasional tillage within no-tillage (NT) systems, on nematode communities in corn-soybean cropping systems in Ontario, Canada using metabarcoding approach. Soil samples were collected at 0-5 cm and 5-20 cm depths during planting and before harvesting of corn/soybeans in 2021 and 2022. The results showed that tillage significantly influenced nematode community structure and distribution within the soil profile. Beneficial free-living nematodes were abundant at 0-5 cm (> 70%), while herbivores dominated at 5-20 cm. The MT and NT systems supported a higher relative abundance of bacterivores, particularly Rhabditis, at both depths. Bacterivore populations were 1.7 times higher in MT than in CT at the corn/soybean maturity stage. The CT system favoured herbivore nematodes, especially Pratylenchus, with 47% higher populations at 0-5 cm and 76% higher at 5-20 cm compared to MT and NT. The CT was initially characterized by high maturity index and structure index values, possibly due to legacy effects; however, both metrics declined over time, whereas values under NT increased. The plant-parasitic index was elevated in both CT and NT but differed in the dominant functional guilds. The nematode channel ratio was higher under CT and MT, signaling a stronger bacterial pathway, while NT gradually shifted toward a more fungal microbial channel. The soil organic matter (OM), total carbon and total organic carbon were significantly higher at the 0-5 cm depth in the MT and NT systems. Correlation analysis identified pH, OM, total nitrogen and cation exchange capacity as the key soil properties shaping the structure of nematode communities. Our findings suggest that MT and NT can enhance soil health and long-term resilience against herbivores in corn-soybean cropping systems.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".